Vision:
0% chance to be seen at outset of game.
0% chance to be seen at outset of game if independent.
Not always seen even if terrain has been seen.
Occupants not seen even if unit has been seen.
Can see units up to 4 cells away.
Vision is line-of-sight.
Chance to see if adjacent is 200% by default, 10% for spy-plane, stormcloud, 5% for submarine, mine, 100% for ankheg.
Chance to see in general is 100% by default, 5% for submarine, ankheg, mine, 10% for spy-plane, stormcloud.